Textile dry cleaning machine

ABSTRACT

In a textile dry cleaning machine having a system for recirculating air in a closed cycle through a heating station, through a drum wherein a textile to be cleaned is contacted with cleaning fluid and thereafter spin-dried, and then through a cooling station to vaporize and recover residual cleaning fluid remaining in the textile after spin-drying, the provision in the air recirculating system of a regulatable branch path by-passing the heating station and drum for feeding a controlled proportion of the circulated air stream containing vaporized cleaning fluid directly to the cooling station along with the part thereof fed to the cooling station through the heating station and drum. Increase in efficiency of fluid recovery is obtained thereby, as a result of the temperature differential between the two parts fed to the cooling station. The recovery system is particularly useful and economical for dry cleaning machines which work with derivatives of the methane and ethane series as cleaning fluid, and can also be applied with advantage to machines that work with tri- or tetrachloroethylene.

J aeger 51 Jan. 23, 1973 [54] TEXTILE DRY CLEANING MACHINE [76] Inventor: Walter Jaeger, Wilhelmstrasse 33,

Neureut bei Karlsruhe, Germany [22] Filed: Nov. 12, 1970 [2i] Appl. No.: 88,820

Primary Examiner-William I. Price Attorney-Jennings Bailey, in

[57] 1 ABSTRACT in rain; diyeiesangiaaeiiae" having a system for recirculating air in a closed cycle through a heating station, through a drum wherein a textile to be cleaned is contacted with cleaning fluid and thereafter spin-dried, and then through a cooling station to vaporize and recover residual cleaning fluid remaining in the textile after spin-drying, the provision in the air recirculating system of a regulatable branch path bypassing the heating station and drum for feeding a controlled proportion of the circulated air stream containing vaporized cleaning fluid directly to the cooling station alo ng with the part thereof fed to the cooling station through the heating station and drum. Increase in efficiency of fluid recovery is obtained thereby, as a result of the temperature differential between the two parts fed to the cooling station. The recovery system is particularly useful and economical for dry cleaning machines which work with derivatives of the methane and ethane seriesas cleaning fluid, and can also be applied with advantage to machines that work with trior tetrachloroethylene.

2 Claims, 1 Drawing Figure PATENTEDJAH 23 ms 3,712,088

INVENTOR wfii gTEQ MZGER aux? TEXTILE DRY CLEANING MACHINE BACKGROUND OF THE INVENTION In conventional textile dry cleaning machines which work with trior tetrachloroethylene as cleaning fluid, the textile to be cleaned is first washed with the cleaning fluid, then spin-dried, then dried with heated recirculated air, and finally aired with fresh air, in four operational phases which follow one another automatically. The drying phase with heated recirculated air, which circulates in a cycle and in so doing passes through a cooling station, serves not only to remove from the textile, but also to the greatest possible extent to recover, the proportion of cleaning fluid still contained in the spin-dried material. The ensuing and final treatment with fresh air can almost completely remove the last traces of trior tetrachloroethylene still remaining, and is effected by blowing if off to the atmosphere. This is necessary in view of the unpleasant smell of trior tetrachloroethylene, and its removal by blowing off is economically acceptable since trior tetrachloroethylene is comparatively cheap.

The recovery of the cleaning fluid in the drying phase, to which particular attention has always been given for reasons of economy, is effected by the recirculated air current, which becomes enriched with vaporized cleaning fluid in flowing through the spindried cleaned textile in the machine drum, being heavily cooled down in the cooling station, so that a proportion of the cleaning fluid in vapor form contained in the recirculated air condenses and can be drained off at the bottom of the cooling unit. The proportion which can thus be recovered is determined primarily by the boiling point of the cleaning fluid, if the cooling or refrigeration capacity of the cooling unit is assumed as constant.

With dry cleaning machines using tri or tetrachloroethylene, the boiling points of which lie at about 80 to 120C, charging of the cooling unit with cooling water at about C will result in a large proportion of the trior tetrachloroethylene contained in therecirculated air being condensed. If, on the other 'hand, derivatives of the methane and ethane series are used as cleaning fluid, and especially fluorinated chloro-hydrocarbons such as Freon which has very considerable advantages over tetrachloroethylene on account of its lower aggressiveness to textiles, its absolute non-toxicity and odorlessness, then the temperature in the cooling station must be considerably lower, since the boiling point of Freon lies at about C.

In dry cleaning machines that work with Freon" it is known to provide a heating station for heating the recirculated drying air to a suitable temperature of about to C, and a refrigerating unit for cooling the recirculated air to about 0C, to ensure condensation of a large proportion of the Freon" contained in the recirculated air.

Because the price of fluorinated chloro-hydrocarbons, again taking Freon" as an example, is substantially higher than that of trior tetrachloroethylene, the degree of efficiency of recovery is an especially important factor in the case of use of Freon" as cleaning fluid. Also, it is not economically tolerable in this case to blow out the last traces of fluid from the textile, as is done with the cheaper trior tetrachloroethylene.

Although recovery of Freon" contained in the recirculated air could be substantially increased by lowering the cooling temperature prevailing in the cooling unit to substantially below 0C, the operating cost of the dry cleaning machine would thereby be quite disproportionately increased. Apart from the extra expense for the refrigeration, additional extra expense would be necessary for the heating in the heating station, because the recirculated air coming from the heating station must at all cost have been warmed to at least 0C, otherwise the residual water vapor contained in the recirculated air would deposit as ice in the refrigerating unit and impair its efficiency, necessitating the installation of a thawing device.

OBJECTS AND SUMMARY OF THE lNVENTlON It is therefore an object of the present invention to provide a textile dry cleaning machine with means for improving the efficiency of recovery of cleaning fluid from the drying phase abovementioned, and especially for a machine that works with derivatives of the methane and ethane series as cleaning fluid, in particular fluorinated chlorohydrocarbons, for example Freon".

Another object of the invention is the provision of means to effect such improvement while at the same time avoiding increase of working costs such as would arise for increased cooling capacity in the cooling unit, or increased heating at the heating station, or due to blowing off of last residues of cleaning fluid into the atmosphere. A further object is to achieve the foregoing objects with means capable of simple and economical assembly.

According to the invention, a textile dry cleaning machine of the kind mentioned is provided with an air circulating system for circulating air through the heating station, drum and cooling station in the drying phase, the system including a branch path by-passing the heating station and drum and passing direct to the cooling station. Thus, while the main circulatory cycle for the air, which is mixed with the cleaning fluid vaporized thereby during passage through the drum, is passed through the heating station, drum and cooling station, a portion of the mixture stream being recirculated from the cooling station is re-fed directly to the cooling station, by-passing the heating station, and forced in a closed cycle with the main stream of the mixture repeatedly through the cooling station. With this machine, the prior art practice of airing the cleaned textile by blowing out to atmosphere is eliminated and avoided.

The by-passing withdrawal of a portion of the mixture of air and cleaning medium before the heating has the effect that the temperature of that portion arriving at the cooling station is substantially lower than if the whole of the mixture were fed to the cooling station only after passing through the heating system and the spin-dried textile in the drum, as is the case in the cleaning machines known hitherto. Consequently, the vapor pressure of the cleaning medium, corresponding to this lower mixture temperature, also drops, with the result that the endeavor of the cleaning medium to pass over into the liquid phase increases. Thereby an increase in recovery of cleaning fluid is achieved, and without the necessity of increasing the heating or cooling capacity of the dry cleaning machine.

Further advantages and features of the invention appear from the following description read with the accompanying diagrammatic drawing which depicts such parts only as are necessary to illustrate the invention.

In the drawing, 1 designates a heating station or unit, 2 a drum, 3 a cooling station or unit, 4 an air circulating device, or blower, S a regulating valve and 6 a fluff catcher or trap. The circulating device 4 drives the mixture of air and vaporized cleaning fluid partially to and through the heater 1 and the drum 2 to the cooler 3 along one path shown through these, and partially directly to the cooler 3 along the branch path shown containing valve 5. From cooler 3 the mixture is sucked in again by the circulating device 4 and recirculated as before. The proportion of mixture flowing along the bypass directly to the cooler 3 can here be adjusted by means of the regulating valve 5. The mixture leaving the drum 2 is freed of fluff and the like by passage through the fluff trap 6.

The air mixture is heated in the heater 1 to a suitable temperature of about 20 to 30C, for drying a textile which has been cleaned with the cleaning fluid and then spin-dried in the drum 2. The circulated gas mixture in the drum 2 vaporizes and absorbs cleaning fluid as well as water still remaining in the spin-dried textile. In the cooler 3 the gas mixture fed into it is cooled down to temperatures little above C, whereby the major part of the vapor of cleaning fluid is removed from the gas mixture by condensation on the cooling surfaces of the unit 3 and is recovered. The proportion of the circulated gas mixture which is by-passed through the regulating valve and fed directly to the cooler 3 has a substantially lower temperature than the circulated gas mixture of the main cycle, since the bypassed portion did not pass through the heater 1. Consequently, in the cooler 3 the by-passed portion cools down more quickly and to a lower temperature, and thus during the constant passage time becomes more rapidly poorer in cleaning medium content, than the mixture of the main cycle path through heater 1. Since the by-passed portion rejoins the main cycle path after passage through the cooler 3 or even within the latter, the final cleaning medium content which establishes itself asymptotically is substantially lower than if the whole of the circulated gas mixture were passed through the heater 1.

The provision of the auxiliary cycle path branched off at the regulating valve 5 works especially effectively, since the gas mixture passed through the branch does not have to overcome pressure losses through the heater 1 and especially through the spin-dried textile in the drum 2.

The invention enables economic working to be achieved with derivatives of the methane and ethane series as the cleaning fluid, and particularly fluorinated chlorohydrocarbons such as Freon", in a dry cleaning machine with elimination of the final operation of airing the cleaned textile by blowing out to the atmosphere as provided in the conventional dry cleaning machines. The invention is also usable to improve the efficiency of the conventional dry cleaning machines which work with trior tetrachloroethylene.

lclaim:

1. in a textile dry cleaning machine, the combination with a drum wherein textile to be dry cleaned is contacted with dry cleaning fluid and thereafter spin-dried of an air recirculating system for drying the spin-dried textile to remove therefrom and recover residual cleaning fluid, said system comprising air heating means, air cooling means, a blower, conduit means connecting said heating means, said cooling means, said blower and said drum to form a closed circuit for air flow having said heating means located upstream of, and said cooling means located downstream of, said drum, and conduit means branched off from said circuit at a point upstream of said heating means and connected to the input side of said cooling means to form a by-pass path for air flow direct to said cooling means by-passing said heating means and said drum. 2. The combination of claim 1, said system including a by-pass regulating valve for controlling the proportion of the recirculated airstream that is by-passed direct to said cooling means. 

2. The combination of claim 1, said system including a by-pass regulating valve for controlling the proportion of the recirculated airstream that is by-passed direct to said cooling means. 